Lecture 1 - Foundational genetics Flashcards
Define: Genetics, genes alleles chromosomes genotype phenotype
Genetics - study of heredity (passing on traints)
Genes - stretch of DNA which determines the structure and function of a molecule
Chromosomes - where genes are located
Alleles - variants in genes
Genotype - genetic constitution of individuals
Phenotype - physically observable trait
What are dominant and recessive genes?
dominant are genes that prevent other genes from being expressed and recessive are genes that might not show even if they are present.
What is homozygous or purebred?
when gene pairs are the same
What is heterozygous or hybrid?
when there is one dominant and one recessive gene
What are the mendelian underlying principals of genetics?
- segregation
- dominance
- independent assortment
What is Mendel’s first law?
Segregation where the cells containing two alleles separates during meiosis forming a gamete with just one copy of each gene
What is Mendel’s second law?
Independant assortment refering to independent gene separation during gamete formation due to random alignment
What are the exceptions to Mendel’s principals?
Incomplete dominance where the phenotype of the offspring is intermediate between the parent’s phenotype.
( Dominant red parent and recessive white parent = heterozygous pink offspring).
Codominance where both alleles are expressed (white and black ‘speckled’ chickens).
What are linked genes?
Genes on the same chromosome which tend to be inherited together.
What are sex-linked traits?
Genes which are located on ONLY the X chromosome. X linked alleles will ALWAYS show in males whether they are dominant or recessive because males only have one X chromosome.
What are examples of RECESSIVE sex-linked disorders?
Colour blindness and haemophilia.
What are polygenic traits?
Single trait which is influenced by many genes.
What are examples of qualitative traits?
Skin colour, eye colour and height.
